Sound-modifying disk for radio or phonograph receivers



H. w. MOURAR SOUND MODIFYING DISK FOR RADIO OR PHONQGRAPH RECEIVERS April -1 6 192 9.

Filed Feb. 8. 1924 H {dW byhig w Moumr Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

HAROLD W. MOURAR, OF NORTH COVENTRY TOWNSHIP, CHESTER COUNTY, PENNSYL- VANIA,

SOUND-MODIFYING DISK FOR RADIO OR PHONOGRAPH RECEIVERS.

Application filed February 8, 1924. Serial No. 691,361.

phragm mingles with the sounds it reproduces merely through the vibrations produced electrically or mechanically, sounds arising from the bending of the material These latter sounds are loudest nearest the edges of the diaphragm where it is held between two clamping portions of the diaphragm holder. The hard, uniform material of the diaphragm cannot reproduce with much exactness a sound wave produced by the soft vocal chords that vary in size, shape and tension. The present device lessens the metallic sounds by mufiling the sounds arising from the edges of the metallic diaphragm and lessens the uniformity of the sound wave reproduced by the vibrations of the metallic diaphragm through the impulse of the variations of the electric current or through the mechanical impulse transmitted to the diaphragm through the needle. I

Fig. 1 is a sectional view on line 1-1 of Fi 4. Fig. 2 is a plan view of a modifying dis Fig. 3 an edge view of the modifying disk. Fig. 4 a side elevation of the holders for the disk and diaphragm, the position of the diaphragm and disk being indicated by dotted lines. 7

The modifying disk 1 is made of celluloid, pyraline or some other suitable nitro-cellulose material which is highly resilient. It is of substantially equal diameter with the diaphragm Its best thickness approximates that of the ordinary photograph film. It has anv outer ring, 4, that is solid. Inwardly projecting from this ring is a fringe formed of the material of the disk. Each member of this fringe is pointed at its inner end, and iswidened at its outer end where it becomes integral with the outer ring, 4. These fringe members are highly irregular in length and in width, where they join the ring, 4. Many of them curl, others bend in various directions so that the mouth, 3, is irregular in its orifice; and the density of the fringe varies irregularly throughout the fringe area. The resiliency and mobility of the fringe area also varies irregularly because of the irregularity in the width, length, curl and bending of the fringe members. The disk, 1, is placed in the diaphragm holder, 8, on top of the diaphragm. 6, and is clamped down upon the diaphragm by the clampmg part, 9, the position of clamping of the part, 9, being indicated on Fig. 2 by the dotted line. 7 indicates the position of the horn.

The outer ring, 4, is quite irregular in width as the cuts making the fringe end outwardly at varying distances from the edge of the disk. The mouth, 3, is also quite irregular in outline.

The outer ring, 4, of the the portions .of the diaphragm, 6, lying toward itscircumference, and mufiles the metallic sounds that arise most largely from that area of the diaphragm. The wider bases of the fringe elements continue this mufliing to some extent inward from the outer part of the fringe area. This mufliing diminishes rapidly toward the inner edge of the fringe area, and at the mouth, 3, where the least mechanical noise arises, there is no muliling. The hardness of tone which arises from a metal diaphragm that has a very uniform vibration is lessened by combining with it a fringe of nitro-cellulose material. The nitro-cellulose material has a physical structure resembling in quite a number of ways the structure of the tissue of the vocal organs. This tends to change the quality of vibrations given off b the diaphragm. The variation in the sti ness, length and bending of the frin e elements tends also to produce an irregu arity in the sound waves, approximating their irregularity when emitted by the human vocal organs.v The irregularity of the width of the ringA, and of the mouth, 3, also aids in producing the desired result. Of

course, some of the features of my device may be omitted with their corresponding functions but for the best and mostv complete effects the little disk should be used as above described.

I claim:

1. In. a receiver, the combination with a metallic diaphragm and clamping members therefor, of an annular disk of nitro-cellulose material placed adjacent to said diaphragin and clamped against it by the said clamping members, said annular disk consisting of an annular portion adjacent to the circumference and having a fringe formed of the material of this disk extending inwardly from this annular portion and a mouth having its orifice lying within the ends of the fringe.

2. The combination set forth in claim 1 in which the fringe is irregular in length and has the ends of its inwardly projecting parts lying in different planes.

3. The combination set forth in claim 1, in which the orifice of the mouth is irregular in shape.

4. The combination as set forth in claim 1,

in which the density of the fringe varies irregularly throughout the fringe area.

5. The combination set forth in claim 1, in which the fringe is irregularly curved.

6. The combination set forth in claim 1, in which the fringe is irregular and has the ends of its inwardly projecting parts lying in different planes.

HAROLD W. MOURAR. 

